Ultralow-Density, High-Modulus, and High-Strength RSP Al-Li-Be Alloys

Aluminum-lithium-beryllium alloys have been prepared by melt spinning, using prealloyed arc-melted buttons. The alloy ribbon was comminuted and cold compacted to 30 to 50% density, vacuum hot pressed to 100% density, and extruded. The bar product was subsequently solution heat treated, quenched, and aged. The microstructure of the alloys consists of a relatively featureless matrix containing a homogeneous dispersion of fine beryllium particles, mostly 50 to 500 nm in size. The results of heat treatment show that the alloys respond to age hardening in a manner similar to that of binary Al-Li alloys. Preliminary results on the mechanical properties and their relationships with microstructural features are presented for the Al-Li-Be alloys, as well as their potential for weight savings. The authors estimate that these monolithic aluminum alloys may exhibit specific strength and elastic modulus values comparable to those of the best whisker or particulate metal-matrix composites, while showing concomitant high weight savings.